1. Field of the Invention
The present invention relates generally to materials for the immunologic removal of proteins and other species from biological fluids, and more particularly to an immunoadsorbent material for removing IgM and IgM-related complexes from blood.
The extracorporeal treatment of blood to remove immunoglobulins and circulating immune complexes may be useful in a variety of circumstances. For example, the removal of circulating IgM and IgM-related complexes may have therapeutic value in the treatment of primary biliary cirrhosis (PBC). PBC is a syndrome of disordered immune regulation associated with increased levels of immunoglobulins (primarily IgM) in the blood, increased levels of circulating immune complexes, the presence of auto-antibodies, and altered T and B cell function.
It would be desirable to provide substances capable of removing IgM and IgM-related compexes from a patient's blood. It is particularly desirable that the substances be convenient to use, sterile, and avoid the release of toxic substances into the blood being treated.
b 2. Description of the Background Art
Blood treatment systems for the removal of anti-A and anti-B antibodies are described by Bensinger et al. (1981) N. Engl. J. Med. 304:160-162 and Bensinger et al. (1982) J. Clin. Apheresis 1:2-5. The immunoadsorption system utilizes synthetic human blood group antigens covalently linked to a silica matrix. The use of a protein A-silica column for extracorporeal immunoadsorption is briefly reported by Bensinger et al. (1982) N. Engl. J. Med. 306:935. "Affinity Chromatography - Principles and Methods" published by Pharmacia Fine Chemicals, Uppsala, Sweden, teaches that carbodiimide coupling to Sepharose.RTM. is best performed at a pH above 4.5.